Friends fear “Harry Potter” actor DANIEL RADCLIFFE is spiraling out of control with a dan­gerous drug and booze habit  – just like “Home Alone” child star Macaulay Culkin!

Sources say Radcliffe leads a secret party-hearty lifestyle that’s taking a toll on his health, and exclusive photos reveal the 24-year-old has morphed from the fresh-faced boy wizard into a gaunt, sweaty, bleary-eyed mess!

“Daniel looks like death warmed over,” a friend told The ENQUIRER. “It’s nothing for him to knock back vodka shots, tequila shots and whiskey sours. There’s real fear among his friends that he’s turning from booze to drugs.”

Radcliffe has been quoted as telling pals: “I love weed.” A headline in his native Britain even referred to him as “Harry Pothead,” although he denied smoking marijuana at the time.

A Radcliffe representative said stories of Radcliffe’s drinking or doing drugs are “absolute­ly untrue.”

The actor claimed to quit drinking in 2010 after suffering blackouts, but The ENQUIRER reported that he fell off the wagon in late 2012 during a partying binge in the Big Apple.

Radcliffe – who’s amassed an $86 million fortune thanks to the “Harry Potter” series – has no steady girlfriend.

“Daniel’s had a string of girl­friends, but none of them stick,” said the source. “He can’t find love, but he doesn’t like to be alone. So he goes out and parties with questionable characters.”

Radcliffe reportedly looked strung-out while partying at the London nightclub Embargo 59 recently, with an eyewitness say­ing he “was bumping into people and the walls.”

Other photos show Radcliffe looking shockingly haggard, his eyes sunken in huge dark circles, while signing autographs in early August outside a London theater where he’s performing.

Experts who reviewed the photos at The ENQUIRER’s request warn that Radcliffe could be headed for trouble.

“He’s pale and gaunt, and his eyes are inflamed, which could indicate alcohol abuse or drug use,” Dr. Damon Raskin, an addiction specialist from Pacific Palisades, Calif., who has not treated Radcliffe, told The ENQUIRER. “Even at 24 years of age, alcohol abuse could kill him. Based on his appearance, I would bring him in for complete medical testing.”

Dr. Gregory Smith, producer of the documentary “American Addict,” has not treated Radcliffe, but calls his appearance “alarming.”

“He could have relapsed and returned to drinking or he could have switched his addiction to drugs, which is quite common,” said Dr. Smith, an addiction specialist from Los Angeles, Calif.

“Judging from his appearance, I’m concerned that he’s in danger.”

Friends worry Radcliffe could follow in the footsteps of Culkin who, as The ENQUIRER has reported, has battled addictions to heroin and the powerful prescription painkiller oxycodone. He looked as haggard as Radcliffe does now.

“Daniel has been working nonstop since the age of 11,” said another pal.

“He needs to get himself cleaned up. No one wants to see him end up like Macaulay Culkin.”